Internal Rotation And Chlorine Nuclear Quadrupole Coupling In 2-chloro-4-fluorotoluene Explored By Microwave Spectroscopy And Quantum Chemistry

Nguyen, Ha Vinh Lam

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https://hdl.handle.net/2142/111411 Copy

Description

Title

Internal Rotation And Chlorine Nuclear Quadrupole Coupling In 2-chloro-4-fluorotoluene Explored By Microwave Spectroscopy And Quantum Chemistry

Author(s)

Nguyen, Ha Vinh Lam

Contributor(s)

• Lesarri, Alberto
• Bailey, William C.
• Grabow, Jens-Uwe
• Obenchain, Daniel A.
• Herbers, Sven
• Nair, K.P. Rajappan

Issue Date

2021-06-23

Keyword(s)

Mini-symposium: Large Amplitude Motions

Abstract

2-Chloro-4-fluorotoluene was investigated using a combination of molecular jet Fourier transform microwave spectroscopy in the frequency range from 5 to 21 GHz and quantum chemistry. The molecule experiences an internal rotation of the methyl group, which causes a fine splitting of all rotational transitions into doublets with separation on the order of a few tens of kHz. In addition, hyperfine effects originating from the chlorine nuclear quadrupole moment coupling its spin to the end-over-end rotation of the molecule are observed. The torsional barrier was derived using both the rho\footnote{A. Belloche, A.A. Mescheheryakov, R.T. Garrod, V.V. Ilyushin, E.A. Alekseev, R.A. Motiyenko, I. Margules, H.S.P. Müller, K.M. Menten, \textit{Astron. Astrophys.} \textbf{601}, A49 (2017).} and the combined-axis-method,\footnote{H. Hartwig, H. Dreizler, \textit{Z. Naturforsch.} \textbf{51a} 923 (1996).} giving a value of 462.5(41) \wn. Accurate rotational constants and quadrupole coupling constants were determined for two $^{35}$Cl and $^{37}$Cl isotopologues and compared with Bailey’s semi-experimental quantum chemical predictions.\footnote{W.C. Bailey, \textit{J. Mol. Spectrosc.} \textbf{209} 57 (2001).} The gas phase molecular structure was deduced from the experimental rotational constants supplemented with those calculated by quantum chemistry at various levels of theory. The values of the methyl torsional barrier and chlorine nuclear quadrupole coupling constants were compared with the theoretical predictions and with those of other chlorotoluene derivatives.\\

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

Text

Language

eng

Permalink

http://hdl.handle.net/2142/111411

DOI

10.15278/isms.2021.WA03

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